In the past, various types of case handling machines have been developed. Case handling machines include machines for assembling cases, machines for sealing cases and machines for placing insert in cases, plus various combinations thereof. For example, some case handling machines both assemble and partially seal cases. Other case handling machines merely seal cases. In some instances, sealing is accomplished using an adhesively coated tape. In other cases, an adhesive is applied directly to the major and/or minor flaps of the case to be sealed. In some instances, both the bottom and the top of the cases are sealed after the case has been loaded with the object or objects to be stored in the case. In such instances, the case is partially assembled and, then, loaded. More specifically, the case is erected and the bottom major flaps folded over the bottom minor flaps. The top major and minor flaps of the case are left upstanding. The objects are loaded into the case as the case is supported by a suitable support medium, such as a conveyor. Thereafter, the case is conveyed to a case sealing machine that seals the bottom of the case at the same time the top is sealed. The present invention relates to the latter type of case sealing machines, i.e., case sealing machines having the capability of simultaneously sealing both the top and bottom of cases, or sealing either the top or the bottom of cases, as desired.
In the past, case sealing machines designed to seal both the top and/or bottom of cases have been either entirely manually controlled or semi-automatically controlled by a plurality of sensing switches actuated by lever arms impinged on by the case, as the case is moved through the machine. Manually controlled machines are undesirable because they are both slow and labor intensive. Semi-automatically controlled electro-mechanical machines have a number of other disadvantages. First, because sealing machines use glue to seal cases, glue is often spattered. Glue spatterd on sensing switches frequently affects the operation of such switches, often resulting in incorrect machine operation. When this occurs, the machine must be shut down and corrective cleaning and/or repair steps taken. Dirt and/or other debris present in the environment in which case sealing machines are used also can affect the operation of sensing switches. Also because sensing switches deteriorate relatively rapidly when opened and closed frequently, frequent switch replacement is often required. Another major disadvantage of prior art electro-mechanical machines is the difficulty in changing the manner and operation of such machines. Usually a switch arm must be re-adjusted and/or a timing wheel peg must be repositioned to change the relationship of an operative element (e.g., glue actuator, T-deck, kicker, etc.) and either the case or a timing wheel. Such changes require the services of tools and a mechanic. All of these disadvantages contribute to machine down time. Machine down time is undesirable for two reasons--the cost of related machine repair; and, the resultant idle time of the machine operator and employees filling the cases being sealed by the machine.
Thus, there is a need for a case sealing machine that uses a minimum number of position sensing switches, yet can be easily programmed to seal the top, bottom or both the top and bottom of a case as a case is moved through the machine, particularly such a machine formed of reliable integrated circuits that are readily programmable. The present invention is directed to providing such a machine.